Serpentine drive belts are becoming increasingly durable due to the use of EPDM materials. As a result, a normally reliable indicator of belt wear, cracking, is occurring less frequently although belts are still wearing. Such wear is difficult to visually diagnose and can lead to performance problems in the accessory belt drive system, for example, slipping and noise.
Belt wear in multi-ribbed belts manifests as an increase in belt groove width and depth, which results from wear and reduction in size of the belt ribs adjacent to the groove.
Representative of the art is U.S. Pat. No. 3,732,626 (1973) to Miller, Jr. which discloses an involute-spline, wear-step measurement gage comprising three coaxial and relatively rotatable splines. Springs are provided to bias a first spline in one rotary direction and the other two splines in the opposite direction when the gage has been placed on or in the spline to be measured and actuated. The first spline engages the unworn (non-drive) surface of the spline being measured and the other two splines are of different radial dimensions so that one of them engages the wear step and the other engages the unworn portion of the original involute, i.e., the form clearance, adjacent the wear step. A dial indicator arrangement registers the difference in positioning of these latter two splines in terms of the magnitude of the wear step.
What is needed is a belt wear gauge comprising an arcuate surface having a predetermined radial dimension wherein engagement of the elongate member within a belt groove and the position of the tactile surface relative to a datum plane at a tip of belt ribs disposed immediately adjacent to the belt groove indicates a state of wear of the belt ribs. The present invention meets this need.